Washington chemical tank was called unfit for service before deadly failure, investigators find

Investigators have found that a chemical tank at a Washington state paper mill was deemed "not fit for continued service" 10 months prior to its deadly failure in May. The catastrophic rupture occurred on May 26 in Longview, expelling a massive volume of caustic liquid with enough force to blow out building walls.

The findings were released as an update by the U.S. Chemical Safety Board, which is conducting an ongoing investigation into the incident. While federal authorities have revealed the prior warning regarding the tank's condition, the official cause of the failure remains under determination.